Synthesis Of Propyl Gallate Catalyzed By Keggin Heteropolyacid Supported On Cucurbit[6]urils

Propyl gallate compounds also have significant pharmacological and biological activity,can effectively eliminate free radicals,and are used for anti-oxidation and anti-microbial.Therefore,it is also widely used in the fields of medicine,cosmetics,feed and so on.The current methods for producing propyl gallate include chemical catalysis and biotransformation.The catalysts used are:p-toluenesulfonic acid,sodium bisulfate,strongly acidic ion exchange resin,sulfuric acid,phosphoric acid,heteropolyacid,and A.flavus cells.The chemical catalytic energy consumption is large,the environment is polluted,the preparation time is long,the side reaction products are many,and the equipment is severely corroded.The further utilization of this method has limitations;while the biotransformation is more and more due to the advantages of mild conditions,few by-products,and high product purity.More favored.Heteropoly acid has unique physical and chemical properties such as redox and acidity,which makes it have a wide range of application prospects in real life.However,because it can be dissolved in most solvents,its subsequent separation is difficult,and the catalyst is not easily separated from the product used in the catalytic reaction.Load is the simplest and most effective way to solve this problem.Therefore,it is very important to find a suitable carrier for heteropoly acid.Because of its charged negative carbonyl oxygen atom port,Cucurbit[n]urils?Q[n]?can interact with some cationic groups,and it also has a unique cavity structure.According to the size of the cavity,it can accommodate guest molecules of different sizes.In addition,due to the solubility of ordinary Cucurbit[n]urils?Q[n]?,which limits the further research and application of Cucurbit[n]urils?Q[n]?,modified Cucurbit[n]urils?Q[n]?were born.Among them,the outer wall of the TMe Q[6]is composed of four methyl groups,which makes it positively charged and can interact with the anionic group through hydrogen bonding and ionic dipole.It is precisely because of this This kind of outer wall makes it possible to form an assembly with excellent properties with heteropoly acid.Thus,the heteropolyacid is immobilized,and this assembly has a wide range of practical applications.In this paper,supramolecular self-assembly is carried out by using the positively charged outer wall of the Cucurbit[n]urils?Q[n]?and the negatively charged heteropolyacid anion.It not only preserves the structural characteristics and corresponding chemical properties of polyacids,but also is a solid substance that is hardly soluble in acids,alkalis and organic solvents,can achieve heterogeneous catalysis,and solves the problem that the catalyst cannot be used in the esterification reaction.Disadvantages such as recycling and non-reusable.The catalyst was used to catalyze the synthesis of propyl gallate,and the defects and catalytic efficiency of the original catalyst were improved.The main research contents are as follows:1.Using water as the medium,a TMe Q[6]was selected,which was respectively combined with three typical Keggin-type heteropoly acids?HPAs?,silicotungstic acid?STA?,and phosphotungstic acid?PTA?,phosphomolybdic acid?PMA?Supramolecular self-assembly,prepared a series of TMeQ[6]-HPAs supramolecular self-assembly,and X-ray powder diffraction?XRD?,scanning electron microscopy?SEM?,transmission Characterization of electron microscope?TEM?,infrared spectroscopy?FTIR?and so on.The basic properties of the prepared assembly TMe Q[6]-PMA were investigated.Characteristic analysis of ammonia adsorption-desorption?NH₃-TPD?,pyridine infrared?py-FTIR?,specific surface area?BET?and thermogravimetric?TG-DSC?were carried out.2.Through the self-assembly of TMeQ[6]and HPAs,a series of TMeQ[6]-HPAs supramolecular self-assemblies were designed and prepared,and applied to the synthesis of propyl gallate.Through a single factor experiment,the effects of catalyst dosage,acid-alcohol ratio and reaction time on the synthesis of propyl gallate were systematically investigated to select the best reaction conditions.TMeQ[6]-PMA catalyst showed high conversion rate?95.6%?and good stability in the synthesis experiment of propyl gallate.3.Systematically studied the electrochemical performance of TMeQ[6]-PMA self-assembly.By conducting cyclic voltammetry?CV?and constant current charge-discharge?GCD?tests on the assembled button half-cells at room temperature,the cycle reversibility and coulombic efficiency as electrode materials were investigated,and the battery performance was investigated.Systematic research.The charge storage mechanism of TMeQ[6]-PMA self-assembled electrode material as a lithium ion anode material was further studied by evaluating the contribution of the diffusion control process or the surface-limited capacitance effect.